1. Field of Invention
The present invention relates to a method for positioning a viewing center of a parallax barrier, which mainly includes: disposing multiple alignment markers respectively at appropriate places of the parallax barrier and a flat panel display, and performing the position measurement and alignment of multiple alignment markers, so as to achieve a purpose of setting a viewing center at a specific and appropriate position.
2. Related Art
FIG. 1 is a schematic view of a structure and viewing of a conventional parallax barrier 3D display. The parallax barrier 3D image display 10 is mainly formed of a flat panel display screen 11 and a parallax barrier 12. The parallax barrier 12 may be a conventional vertical strip parallax barrier, a conventional slant-and-strip parallax barrier, or a conventional slant-and-step parallax barrier. A coordinate system (X, Y, Z) is set, an XY plane thereof is disposed on a surface of the flat panel display screen 11, and an origin (0,0,0) thereof is disposed at a reference point position CS of the flat panel display screen 11. The reference point position CS may be set at the center of the flat panel display screen 11, or a position close to that center. The parallax barrier 12 is disposed at a position of Z=LB. Likewise, a reference point position CB is also set on the plane of the parallax barrier 12. The reference point position CB may be set at the center of the flat panel display screen 11, or a position close to that center. Thus, a 3D image can be viewed at an optimum viewing distance Z0, and at optimum viewing point PL and PR. Those two optimum viewing points PL and PR are the viewing positions of left and right eyes 13 and 14 of a viewer. A distance between the two optimum viewing points PL and PR is an optimum viewing interval LV. In design, the optimum viewing interval LV is generally equal to the interpupillary distance (IPD) LE. Additionally, the center between the two optimum viewing points PL and PR defines a viewing center CE. Details relevant to the principle and design of a parallax barrier can refer to ROC Patent No. 098128986.
Generally, during practical manufacturing, assembly, and mass production, only when the disposed position between the flat panel display screen 11 and the parallax barrier 12 is particularly positioned and aligned, the viewing center CE can be fixed at a specific and appropriate position.
FIG. 2 to FIG. 5 are schematic views of a viewing center of a parallax barrier with multi-view 3D image.
FIG. 2 is a schematic view of a viewing center of a parallax barrier with 2-view 3D image. The 2-view image is formed of multiple basic units of combined view 21. Each of the basic units of combined view 21 consists of the individual view images 0 and 1 being arranged sequentially from left to right in a unit of a pixel or sub-pixel. There exist multiple optimum viewing points P(1) and P(0) at the optimum viewing distance Z0 for viewing a 3D image. Additionally, due to a relation of even number symmetry, a reference point position CS of the flat panel display screen 11 is just located between the view images 0 and 1, that is, the center position of the basic unit of combined view 21. Thus, for setting of the reference point position CS of the flat panel display screen 11, the optimum position can be set at the center of the basic unit of combined view 21, and the basic unit of combined view 21 is characterized in being the closest to the geometrical center of the flat panel display screen 11. That is to say, the CS can be disposed at the geometrical center of the flat panel display screen or a position close to the center of the flat panel display screen.
FIG. 3 is a schematic view of a viewing center of a parallax barrier with 4-view 3D image. The 4-view image is formed of multiple basic units of combined view 22. Each of the basic units of combined view 22 consists of the individual view images 0, 1, 2, and 3 being arranged sequentially from left to right in a unit of a pixel or sub-pixel. There exist multiple optimum viewing points P(3), P(2), P(1), and P(0) at an optimum viewing distance Z0 for viewing a 3D image. Additionally, due to a relation of even number symmetry, a reference point position CS of the flat panel display screen 11 is just located between the view images 1 and 2, that is, the center of the basic unit of combined view 22. Thus, for setting of the reference point position CS of the flat panel display screen 11, the optimum position can be set at the center of the basic unit of combined view 22, and the basic unit of combined view 22 is characterized in being the closest to the geometrical center of the flat panel display screen 11. That is to say, the CS can be disposed at the geometrical center point of the flat panel display screen or a position close to the center of the flat panel display screen.
For display of an even number-view 3D image as shown in FIG. 2 to FIG. 3, on the XY plane, when the plane of the parallax barrier 12 and the plane of the flat panel display screen 11 are in a state of being plane-parallel without angle rotation, and the reference point position CB of the parallax barrier 12 is consistent with the CS, that is, both the CB and the CS are at a position of the origin (0,0) on the XY plane, the viewing center CE can also be consistent with the CS, that is, the CE is also at the position of the origin (0,0) on the XY plane. Thus, the viewer can view the 3D image at the central position of the screen. Additionally, the CB refers to the geometrical center of the plane of the parallax barrier 12, or a position close to the center, and the position is a center of an opening part of the parallax barrier.
FIG. 4 is a schematic view of a viewing center of a parallax barrier with 3-view 3D image. The 3-view image is formed of multiple basic units of combined view 23. Each of the basic units of combined view 23 consists of the individual view images 0, 1, and 2 being arranged sequentially from left to right in a unit of a pixel or sub-pixel. There exist multiple optimum viewing point P(2), P(1), and P(0) at an optimum viewing distance Z0 for viewing a 3D image. Additionally, due to a relation of odd number symmetry, a reference point position CS of the flat panel display screen 11 is just located at the center of the view image 1, that is, the center of the basic unit of combined view 23. Thus, for setting of the reference point position CS of the flat panel display screen 11, the optimum position can be set at the center of the basic unit of combined view 23, and the basic unit of combined view 23 is characterized in being the closest to a geometrical center of the flat panel display screen 11. That is to say, the CS can be disposed at the geometrical center of a plane of the flat panel display screen or a position close to the plane of the center of the flat panel display screen.
FIG. 5 is a schematic view of a viewing center of a parallax barrier with 5-view 3D image. The 5-view image is formed of multiple basic units of combined view 24. Each of the basic units of combined view 24 consists of the individual view images 0, 1, 2, 3, and 4 being arranged sequentially from left to right in a unit of a pixel or sub-pixel. There exist multiple optimum viewing point P(4), P(3), P(2), P(1), and P(0) at the optimum viewing distance Z0 for viewing a 3D image. Additionally, due to a relation of odd number symmetry, a reference point position CS of the flat panel display screen 11 is just located at a center of the view image 2, that is, a center of the basic unit of combined view 24. Thus, for setting of the reference point position CS of the flat panel display screen 11, the optimum position can be set at a center of the basic unit of combined view 24, and the basic unit of combined view 24 is characterized in being the closest to the geometrical center of the flat panel display screen 11. That is to say, the CS can be disposed at the geometrical center of a plane of the flat panel display screen or a position close to the center of the plane of the flat panel display screen.
For display of an odd number-view 3D image as shown in FIG. 4 to FIG. 5, on the XY plane, when the reference point position CB of the parallax barrier 12 is consistent with the CS, in an X-axis direction, the viewing center CE is deviated a distance of LE/2 from the CS, that is, is deviated the distance of LE/2 to the left or to the right. Thus, the viewer cannot view the 3D image at the central position of the screen. Additionally, the reference point position CB refers to the geometrical center of the plane of the parallax barrier 12, or a position close to the center, and the position is a center of an opening part of the parallax barrier.
The more detailed definitions for the reference point position CB of the parallax barrier 12 and the opening part of the parallax barrier are as shown in FIG. 6 to FIG. 8. The conventional vertical strip, slant-and-strip, or slant-and-step parallax barrier is formed of light-transmissive elements 15 and shielding elements 16. The opening part herein refers to a light-transmissive element 15 of the parallax barrier. Thus, on the plane of the parallax barrier 12, the reference point position CB must be set on the center of the light-transmissive element 15 of the parallax barrier, and the position is the geometrical center of the plane of the parallax barrier 12, or close to the center of the plane of the parallax barrier 12.
In view of the above, as shown in FIG. 2 to FIG. 5, only when the reference point position CB of the parallax barrier 12 is consistent with the reference point position CS of the flat panel display screen 11, the viewing center CE can be fixed at a specific and appropriate position. For display of an even number-view 3D image, on the XY plane, due to a relation of even number symmetry, the viewer can view the 3D image at the central position of the screen, that is, the viewing center CE is consistent with the reference point position CS of the flat panel display screen 11; while for display of an odd number-view 3D image, on the XY plane, due to a relation of odd number symmetry, the viewer cannot view the 3D image at the central position of the screen, and only after deviating the distance of LE/2 to the left or to the right relative to the screen center, the viewer can view the 3D image, that is, the viewing center CE is deviated the distance of LE/2 from the reference point position CS of the flat panel display screen 11. However, for the foregoing ideal state, due to the insufficient assembly and positioning precision, when the reference point position CB of the parallax barrier 12 is inconsistent with the reference point position CS of the flat panel display screen 11, the viewing center is deviated. Additionally, due to the insufficient assembly and repetition accuracy, during the mass production, the viewing center may easily become inconsistent, and cause a low product quality.